drivers/s390/char/tape_char.c

   1 /*
   2  *  drivers/s390/char/tape_char.c
   3  *    character device frontend for tape device driver
   4  *
   5  *  S390 and zSeries version
   6  *    Copyright IBM Corp. 2001,2006
   7  *    Author(s): Carsten Otte <cotte@de.ibm.com>
   8  *               Michael Holzheu <holzheu@de.ibm.com>
   9  *               Tuan Ngo-Anh <ngoanh@de.ibm.com>
  10  *               Martin Schwidefsky <schwidefsky@de.ibm.com>
  11  */
  12
  13 #define KMSG_COMPONENT "tape"
  14 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  15
  16 #include <linux/module.h>
  17 #include <linux/types.h>
  18 #include <linux/proc_fs.h>
  19 #include <linux/mtio.h>
  20 #include <linux/smp_lock.h>
  21 #include <linux/compat.h>
  22
  23 #include <asm/uaccess.h>
  24
  25 #define TAPE_DBF_AREA   tape_core_dbf
  26
  27 #include "tape.h"
  28 #include "tape_std.h"
  29 #include "tape_class.h"
  30
  31 #define TAPECHAR_MAJOR          0       /* get dynamic major */
  32
  33 /*
  34  * file operation structure for tape character frontend
  35  */
  36 static ssize_t tapechar_read(struct file *, char __user *, size_t, loff_t *);
  37 static ssize_t tapechar_write(struct file *, const char __user *, size_t, loff_t *);
  38 static int tapechar_open(struct inode *,struct file *);
  39 static int tapechar_release(struct inode *,struct file *);
  40 static long tapechar_ioctl(struct file *, unsigned int, unsigned long);
  41 #ifdef CONFIG_COMPAT
  42 static long tapechar_compat_ioctl(struct file *, unsigned int, unsigned long);
  43 #endif
  44
  45 static const struct file_operations tape_fops =
  46 {
  47         .owner = THIS_MODULE,
  48         .read = tapechar_read,
  49         .write = tapechar_write,
  50         .unlocked_ioctl = tapechar_ioctl,
  51 #ifdef CONFIG_COMPAT
  52         .compat_ioctl = tapechar_compat_ioctl,
  53 #endif
  54         .open = tapechar_open,
  55         .release = tapechar_release,
  56         .llseek = no_llseek,
  57 };
  58
  59 static int tapechar_major = TAPECHAR_MAJOR;
  60
  61 /*
  62  * This function is called for every new tapedevice
  63  */
  64 int
  65 tapechar_setup_device(struct tape_device * device)
  66 {
  67         char    device_name[20];
  68
  69         sprintf(device_name, "ntibm%i", device->first_minor / 2);
  70         device->nt = register_tape_dev(
  71                 &device->cdev->dev,
  72                 MKDEV(tapechar_major, device->first_minor),
  73                 &tape_fops,
  74                 device_name,
  75                 "non-rewinding"
  76         );
  77         device_name[0] = 'r';
  78         device->rt = register_tape_dev(
  79                 &device->cdev->dev,
  80                 MKDEV(tapechar_major, device->first_minor + 1),
  81                 &tape_fops,
  82                 device_name,
  83                 "rewinding"
  84         );
  85
  86         return 0;
  87 }
  88
  89 void
  90 tapechar_cleanup_device(struct tape_device *device)
  91 {
  92         unregister_tape_dev(&device->cdev->dev, device->rt);
  93         device->rt = NULL;
  94         unregister_tape_dev(&device->cdev->dev, device->nt);
  95         device->nt = NULL;
  96 }
  97
  98 static int
  99 tapechar_check_idalbuffer(struct tape_device *device, size_t block_size)
 100 {
 101         struct idal_buffer *new;
 102
 103         if (device->char_data.idal_buf != NULL &&
 104             device->char_data.idal_buf->size == block_size)
 105                 return 0;
 106
 107         if (block_size > MAX_BLOCKSIZE) {
 108                 DBF_EVENT(3, "Invalid blocksize (%zd > %d)\n",
 109                         block_size, MAX_BLOCKSIZE);
 110                 return -EINVAL;
 111         }
 112
 113         /* The current idal buffer is not correct. Allocate a new one. */
 114         new = idal_buffer_alloc(block_size, 0);
 115         if (IS_ERR(new))
 116                 return -ENOMEM;
 117
 118         if (device->char_data.idal_buf != NULL)
 119                 idal_buffer_free(device->char_data.idal_buf);
 120
 121         device->char_data.idal_buf = new;
 122
 123         return 0;
 124 }
 125
 126 /*
 127  * Tape device read function
 128  */
 129 static ssize_t
 130 tapechar_read(struct file *filp, char __user *data, size_t count, loff_t *ppos)
 131 {
 132         struct tape_device *device;
 133         struct tape_request *request;
 134         size_t block_size;
 135         int rc;
 136
 137         DBF_EVENT(6, "TCHAR:read\n");
 138         device = (struct tape_device *) filp->private_data;
 139
 140         /*
 141          * If the tape isn't terminated yet, do it now. And since we then
 142          * are at the end of the tape there wouldn't be anything to read
 143          * anyways. So we return immediatly.
 144          */
 145         if(device->required_tapemarks) {
 146                 return tape_std_terminate_write(device);
 147         }
 148
 149         /* Find out block size to use */
 150         if (device->char_data.block_size != 0) {
 151                 if (count < device->char_data.block_size) {
 152                         DBF_EVENT(3, "TCHAR:read smaller than block "
 153                                   "size was requested\n");
 154                         return -EINVAL;
 155                 }
 156                 block_size = device->char_data.block_size;
 157         } else {
 158                 block_size = count;
 159         }
 160
 161         rc = tapechar_check_idalbuffer(device, block_size);
 162         if (rc)
 163                 return rc;
 164
 165 #ifdef CONFIG_S390_TAPE_BLOCK
 166         /* Changes position. */
 167         device->blk_data.medium_changed = 1;
 168 #endif
 169
 170         DBF_EVENT(6, "TCHAR:nbytes: %lx\n", block_size);
 171         /* Let the discipline build the ccw chain. */
 172         request = device->discipline->read_block(device, block_size);
 173         if (IS_ERR(request))
 174                 return PTR_ERR(request);
 175         /* Execute it. */
 176         rc = tape_do_io(device, request);
 177         if (rc == 0) {
 178                 rc = block_size - request->rescnt;
 179                 DBF_EVENT(6, "TCHAR:rbytes:  %x\n", rc);
 180                 /* Copy data from idal buffer to user space. */
 181                 if (idal_buffer_to_user(device->char_data.idal_buf,
 182                                         data, rc) != 0)
 183                         rc = -EFAULT;
 184         }
 185         tape_free_request(request);
 186         return rc;
 187 }
 188
 189 /*
 190  * Tape device write function
 191  */
 192 static ssize_t
 193 tapechar_write(struct file *filp, const char __user *data, size_t count, loff_t *ppos)
 194 {
 195         struct tape_device *device;
 196         struct tape_request *request;
 197         size_t block_size;
 198         size_t written;
 199         int nblocks;
 200         int i, rc;
 201
 202         DBF_EVENT(6, "TCHAR:write\n");
 203         device = (struct tape_device *) filp->private_data;
 204         /* Find out block size and number of blocks */
 205         if (device->char_data.block_size != 0) {
 206                 if (count < device->char_data.block_size) {
 207                         DBF_EVENT(3, "TCHAR:write smaller than block "
 208                                   "size was requested\n");
 209                         return -EINVAL;
 210                 }
 211                 block_size = device->char_data.block_size;
 212                 nblocks = count / block_size;
 213         } else {
 214                 block_size = count;
 215                 nblocks = 1;
 216         }
 217
 218         rc = tapechar_check_idalbuffer(device, block_size);
 219         if (rc)
 220                 return rc;
 221
 222 #ifdef CONFIG_S390_TAPE_BLOCK
 223         /* Changes position. */
 224         device->blk_data.medium_changed = 1;
 225 #endif
 226
 227         DBF_EVENT(6,"TCHAR:nbytes: %lx\n", block_size);
 228         DBF_EVENT(6, "TCHAR:nblocks: %x\n", nblocks);
 229         /* Let the discipline build the ccw chain. */
 230         request = device->discipline->write_block(device, block_size);
 231         if (IS_ERR(request))
 232                 return PTR_ERR(request);
 233         rc = 0;
 234         written = 0;
 235         for (i = 0; i < nblocks; i++) {
 236                 /* Copy data from user space to idal buffer. */
 237                 if (idal_buffer_from_user(device->char_data.idal_buf,
 238                                           data, block_size)) {
 239                         rc = -EFAULT;
 240                         break;
 241                 }
 242                 rc = tape_do_io(device, request);
 243                 if (rc)
 244                         break;
 245                 DBF_EVENT(6, "TCHAR:wbytes: %lx\n",
 246                           block_size - request->rescnt);
 247                 written += block_size - request->rescnt;
 248                 if (request->rescnt != 0)
 249                         break;
 250                 data += block_size;
 251         }
 252         tape_free_request(request);
 253         if (rc == -ENOSPC) {
 254                 /*
 255                  * Ok, the device has no more space. It has NOT written
 256                  * the block.
 257                  */
 258                 if (device->discipline->process_eov)
 259                         device->discipline->process_eov(device);
 260                 if (written > 0)
 261                         rc = 0;
 262
 263         }
 264
 265         /*
 266          * After doing a write we always need two tapemarks to correctly
 267          * terminate the tape (one to terminate the file, the second to
 268          * flag the end of recorded data.
 269          * Since process_eov positions the tape in front of the written
 270          * tapemark it doesn't hurt to write two marks again.
 271          */
 272         if (!rc)
 273                 device->required_tapemarks = 2;
 274
 275         return rc ? rc : written;
 276 }
 277
 278 /*
 279  * Character frontend tape device open function.
 280  */
 281 static int
 282 tapechar_open (struct inode *inode, struct file *filp)
 283 {
 284         struct tape_device *device;
 285         int minor, rc;
 286
 287         DBF_EVENT(6, "TCHAR:open: %i:%i\n",
 288                 imajor(filp->f_path.dentry->d_inode),
 289                 iminor(filp->f_path.dentry->d_inode));
 290
 291         if (imajor(filp->f_path.dentry->d_inode) != tapechar_major)
 292                 return -ENODEV;
 293
 294         minor = iminor(filp->f_path.dentry->d_inode);
 295         device = tape_find_device(minor / TAPE_MINORS_PER_DEV);
 296         if (IS_ERR(device)) {
 297                 DBF_EVENT(3, "TCHAR:open: tape_find_device() failed\n");
 298                 return PTR_ERR(device);
 299         }
 300
 301         rc = tape_open(device);
 302         if (rc == 0) {
 303                 filp->private_data = device;
 304                 nonseekable_open(inode, filp);
 305         } else
 306                 tape_put_device(device);
 307
 308         return rc;
 309 }
 310
 311 /*
 312  * Character frontend tape device release function.
 313  */
 314
 315 static int
 316 tapechar_release(struct inode *inode, struct file *filp)
 317 {
 318         struct tape_device *device;
 319
 320         DBF_EVENT(6, "TCHAR:release: %x\n", iminor(inode));
 321         device = (struct tape_device *) filp->private_data;
 322
 323         /*
 324          * If this is the rewinding tape minor then rewind. In that case we
 325          * write all required tapemarks. Otherwise only one to terminate the
 326          * file.
 327          */
 328         if ((iminor(inode) & 1) != 0) {
 329                 if (device->required_tapemarks)
 330                         tape_std_terminate_write(device);
 331                 tape_mtop(device, MTREW, 1);
 332         } else {
 333                 if (device->required_tapemarks > 1) {
 334                         if (tape_mtop(device, MTWEOF, 1) == 0)
 335                                 device->required_tapemarks--;
 336                 }
 337         }
 338
 339         if (device->char_data.idal_buf != NULL) {
 340                 idal_buffer_free(device->char_data.idal_buf);
 341                 device->char_data.idal_buf = NULL;
 342         }
 343         tape_release(device);
 344         filp->private_data = NULL;
 345         tape_put_device(device);
 346
 347         return 0;
 348 }
 349
 350 /*
 351  * Tape device io controls.
 352  */
 353 static int
 354 __tapechar_ioctl(struct tape_device *device,
 355                  unsigned int no, unsigned long data)
 356 {
 357         int rc;
 358
 359         if (no == MTIOCTOP) {
 360                 struct mtop op;
 361
 362                 if (copy_from_user(&op, (char __user *) data, sizeof(op)) != 0)
 363                         return -EFAULT;
 364                 if (op.mt_count < 0)
 365                         return -EINVAL;
 366
 367                 /*
 368                  * Operations that change tape position should write final
 369                  * tapemarks.
 370                  */
 371                 switch (op.mt_op) {
 372                         case MTFSF:
 373                         case MTBSF:
 374                         case MTFSR:
 375                         case MTBSR:
 376                         case MTREW:
 377                         case MTOFFL:
 378                         case MTEOM:
 379                         case MTRETEN:
 380                         case MTBSFM:
 381                         case MTFSFM:
 382                         case MTSEEK:
 383 #ifdef CONFIG_S390_TAPE_BLOCK
 384                                 device->blk_data.medium_changed = 1;
 385 #endif
 386                                 if (device->required_tapemarks)
 387                                         tape_std_terminate_write(device);
 388                         default:
 389                                 ;
 390                 }
 391                 rc = tape_mtop(device, op.mt_op, op.mt_count);
 392
 393                 if (op.mt_op == MTWEOF && rc == 0) {
 394                         if (op.mt_count > device->required_tapemarks)
 395                                 device->required_tapemarks = 0;
 396                         else
 397                                 device->required_tapemarks -= op.mt_count;
 398                 }
 399                 return rc;
 400         }
 401         if (no == MTIOCPOS) {
 402                 /* MTIOCPOS: query the tape position. */
 403                 struct mtpos pos;
 404
 405                 rc = tape_mtop(device, MTTELL, 1);
 406                 if (rc < 0)
 407                         return rc;
 408                 pos.mt_blkno = rc;
 409                 if (copy_to_user((char __user *) data, &pos, sizeof(pos)) != 0)
 410                         return -EFAULT;
 411                 return 0;
 412         }
 413         if (no == MTIOCGET) {
 414                 /* MTIOCGET: query the tape drive status. */
 415                 struct mtget get;
 416
 417                 memset(&get, 0, sizeof(get));
 418                 get.mt_type = MT_ISUNKNOWN;
 419                 get.mt_resid = 0 /* device->devstat.rescnt */;
 420                 get.mt_dsreg = device->tape_state;
 421                 /* FIXME: mt_gstat, mt_erreg, mt_fileno */
 422                 get.mt_gstat = 0;
 423                 get.mt_erreg = 0;
 424                 get.mt_fileno = 0;
 425                 get.mt_gstat  = device->tape_generic_status;
 426
 427                 if (device->medium_state == MS_LOADED) {
 428                         rc = tape_mtop(device, MTTELL, 1);
 429
 430                         if (rc < 0)
 431                                 return rc;
 432
 433                         if (rc == 0)
 434                                 get.mt_gstat |= GMT_BOT(~0);
 435
 436                         get.mt_blkno = rc;
 437                 }
 438
 439                 if (copy_to_user((char __user *) data, &get, sizeof(get)) != 0)
 440                         return -EFAULT;
 441
 442                 return 0;
 443         }
 444         /* Try the discipline ioctl function. */
 445         if (device->discipline->ioctl_fn == NULL)
 446                 return -EINVAL;
 447         return device->discipline->ioctl_fn(device, no, data);
 448 }
 449
 450 static long
 451 tapechar_ioctl(struct file *filp, unsigned int no, unsigned long data)
 452 {
 453         struct tape_device *device;
 454         long rc;
 455
 456         DBF_EVENT(6, "TCHAR:ioct\n");
 457
 458         device = (struct tape_device *) filp->private_data;
 459         mutex_lock(&device->mutex);
 460         rc = __tapechar_ioctl(device, no, data);
 461         mutex_unlock(&device->mutex);
 462         return rc;
 463 }
 464
 465 #ifdef CONFIG_COMPAT
 466 static long
 467 tapechar_compat_ioctl(struct file *filp, unsigned int no, unsigned long data)
 468 {
 469         struct tape_device *device = filp->private_data;
 470         int rval = -ENOIOCTLCMD;
 471         unsigned long argp;
 472
 473         /* The 'arg' argument of any ioctl function may only be used for
 474          * pointers because of the compat pointer conversion.
 475          * Consider this when adding new ioctls.
 476          */
 477         argp = (unsigned long) compat_ptr(data);
 478         if (device->discipline->ioctl_fn) {
 479                 mutex_lock(&device->mutex);
 480                 rval = device->discipline->ioctl_fn(device, no, argp);
 481                 mutex_unlock(&device->mutex);
 482                 if (rval == -EINVAL)
 483                         rval = -ENOIOCTLCMD;
 484         }
 485
 486         return rval;
 487 }
 488 #endif /* CONFIG_COMPAT */
 489
 490 /*
 491  * Initialize character device frontend.
 492  */
 493 int
 494 tapechar_init (void)
 495 {
 496         dev_t   dev;
 497
 498         if (alloc_chrdev_region(&dev, 0, 256, "tape") != 0)
 499                 return -1;
 500
 501         tapechar_major = MAJOR(dev);
 502
 503         return 0;
 504 }
 505
 506 /*
 507  * cleanup
 508  */
 509 void
 510 tapechar_exit(void)
 511 {
 512         unregister_chrdev_region(MKDEV(tapechar_major, 0), 256);
 513 }